The Peak Bloom Date and Blooming Period
The Peak Bloom Date is defined as the day in which 70 percent of the blossoms of the Yoshino Cherry (Prunus x yedoensis) trees are open. The date when the Yoshino cherry blossoms reach peak bloom varies from year to year, depending on weather conditions. dates are set based on the average date of blooming (April 4), but nature is not always cooperative. Unseasonably warm and/or cool temperatures have resulted in the Yoshino cherries reaching peak bloom as early as March 15 (1990) and as late as April 18 (1958).
The Blooming Period is defined as the period that starts when 20% of the blossoms are open and ends when the petals fall and the leaves appear. The Blooming period starts several days before the Peak Bloom Date and can last as long as 14 days; however, frost or high temperatures combined with wind and/or rain can shorten this period.
During the Blooming Period, the National Park Service conducts annual Cherry Tree Walks and bike tours around the Tidal Basin. These Park Ranger conducted programs present an interpretive look at the historical and cultural influence of the Japanese Flowering Cherry Trees in our Nation's Capital. For information on the dates and times of the walks and bike tours please call (202) 426-6841.
It is pretty much impossible to give an accurate forecast much more than 10 days before the Peak Bloom and ach year National Park Service Horticulturists monitor 5 stages of bud development and provide a forecast and updates as needed. The following is a comparative record of past bud development in which 70% of the buds reached each stage:
